Field of the Invention
The present invention relates to a radiation imaging apparatus and a radiation inspection apparatus.
Description of the Related Art
Japanese Patent Laid-Open No. 2002-344809 discloses a radiation imaging apparatus in which each sensor of a sensor array includes a holding unit (sample/hold circuit) which holds a signal corresponding to the radiation dose of irradiation. According to Japanese Patent Laid-Open No. 2002-344809, since the holding units of the respective sensors individually hold signals corresponding to radiation doses, it is possible to simultaneously perform readout of one frame (signal readout) and irradiation of radiation for the next frame.
The radiation imaging apparatus can have an operation mode of obtaining signals with, for example, two sensitivities in each sensor and generating image data by using the signals (for example, an operation mode of performing dynamic range expansion). As one method of implementing this operation mode, there is conceivable a method of providing two holding units in each sensor, holding the signals obtained with the respective sensitivities in the respective holding units, and individually reading out the signals.
Each sensor receives a control signal via a control line arranged in correspondence with the corresponding row of the sensor array. The apparatus performs signal readout by making the signal readout unit read out for each row a signal output from each sensor in response to a control signal. When performing signal readout, this control signal can cause a potential fluctuation at a column signal line for signal readout which intersects with a control line. For this reason, when each sensor from which a signal is to be read out is to be switched, it is necessary to perform signal readout after the settling of the potential fluctuation (after the lapse of a predetermined period). That is, it takes much time to read out signals from the respective sensors of the sensor array. This becomes conspicuous as the size of a sensor panel increases, the number of rows of the sensor array increases, and the wiring capacitance of each signal line increases.